Friedrich Wunderlich; Genesis and environment of the 'Nellenkoepfchenschichten' (lower Emsian, Rheinian Devon) at locus typicus in comparison with modern coastal environment of the German Bay. Journal of Sedimentary Research ; 40 (1): 102–130. doi: https://doi.org/10.1306/74D71F00-2B21-11D7-8648000102C1865D